1. Field of the Invention
The present invention relates in general to a motorcycle engine having a tensioner lifter, a coolant temperature sensor, and other auxiliaries. More specifically, to an arrangement of the auxiliaries.
2. Description of Background Art
In a large-sized engine having four cylinders arranged crosswise relative to the direction of travel of the vehicle, it is easy to dispose a coolant temperature sensor or a cam chain tensioner lifter in a cylinder head. See, for example, Japanese Patent Laid-open No. 2007-262931 (FIGS. 1 and 2). In a small-sized engine, such as a single-cylinder engine, used in a sports motorcycle for off-road operation, however, it is difficult to dispose the tensioner lifter, coolant temperature sensor, and other auxiliaries in the cylinder head due to a small space available in the cylinder head. The auxiliaries are therefore disposed in a cylinder block. See, for example, Japanese Patent Laid-open No. 2007-290640 (FIG. 2).